Chemical Oxidation Method and Compounds

ABSTRACT

A method and system for the reduction of contamination in soil and groundwater is provided. Cyclic oligosaccharides can be used, for example, to carry oxidants, carry activators, solubilize organic contaminants and promote biodegradation.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/333,988, filed Jul. 17, 2014, which is a continuation of U.S.application Ser. No. 13/284,558, filed Oct. 28, 2011, which is acontinuation-in-part of U.S. application Ser. No. 12/464,478, filed May12, 2009, now Issued on Nov. 1, 2011 as U.S. Pat. No. 8,049,056, whichclaims the benefit of U.S. Provisional Patent Application No.61/052,447, titled “Oxidant Stabilization,” filed May 12, 2008. Each ofthese applications is hereby incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made in part with government support under contractFA8903-11-C-8004 awarded by U.S. Air Force Center for Engineering andthe Environment on Sep. 16, 2011. The government may have certain rightsin the invention.

FIELD OF THE INVENTION

The present invention relates generally to the chemical oxidation oforganic contaminants and, in particular, to the stabilizing of ozone forthe purpose of destroying organic contaminants.

BACKGROUND

Both State and Federal governments have issued regulations governinghazardous organic and inorganic contaminants in the environment.Subsurface soil and groundwater contamination with organic and inorganiccontaminants has been the concern of State and Federal government sincethe 1970's. Action levels and clean-up standards have been promulgatedby both State and Federal government for numerous organic and inorganiccontaminants. Regulated organic contaminants in the subsurfaceenvironment include, but are not limited to: polychlorinated biphenyls(PCBs); chlorinated volatile organic compounds (CVOCs) such astetrachloroethene (PCE), trichloroethene (TCE), trichloroethane (TCA),dichloroethene (DCE), vinyl chloride; fuel constituents such as benzene,ethylbenzene, toluene, xylene, methyl tert butyl ether (MTBE), tertiarybutyl alcohol (TBA), polynuclear aromatic hydrocarbons (PAHs), ethylenedibromide (EDB); pesticides such as (but not limited to) DDT; herbicidessuch as (but not limited to) silvex. Regulated inorganic contaminants inthe subsurface environment include: heavy metals, such as lead, arsenic,chromium, mercury, and silver. The State and Federal regulations thatgovern these subsurface contaminants outline a protocol for subsurfaceinvestigation to identify the extent of contamination, identification ofthe human health and ecological risk posed by the contaminants,development of remedial action alternatives for reducing or eliminatingany significant risk posed by the contaminants, and selection andimplementation of remedial measures to achieve the remediation goals.

In situ (ISCO) and ex situ (ESCO) chemical oxidation technologies haveemerged as prominent remedial measures due to cost-effectiveness andtimeliness for achieving remediation goals. This technology can be usedalone or in combination with other complementary technologies, such assoil vapor extraction (SVE) for removal of volatile organic compoundsfrom the unsaturated zone, multi-phase extract for removal of organiccontaminant from the unsaturated and saturated zones, or verticalrecirculation systems in the saturated zone. ESCO can be applied byexcavating subsurface soil and spraying or mixing chemical oxidants intothe soil. ESCO can also be applied to solid surfaces such as vehiclesand equipment.

SUMMARY OF THE INVENTION

In one aspect, a clathrate is provided, the clathrate comprising a hostmolecule and an ozone guest.

In another aspect, a method for the stabilization of ozone is provided,the method comprising adding a cyclic oligosaccharide and ozone to anaqueous medium to produce an ozone clathrate solution.

In another aspect an aqueous solution is provided, the aqueous solutioncomprising a clathrate of ozone and a cyclic oligosaccharide wherein thepH of the solution is between 5.0 and 9.0 and the clathrateconcentration is greater than 0.1 mg/L.

In another aspect a method of reducing the concentration of organiccompound contamination in contaminated material is provided, the methodcomprising forming ozone clathrate, providing the clathrate to thecontaminated material, releasing ozone from the clathrate into solution,and oxidizing the organic compound to reduce the concentration of theorganic compound in the material by at least 50%.

In another aspect, a method of reducing the concentration of an organiccompound in contaminated material is provided, the method comprisingforming a clathrate solution comprising ozone and an oligosaccharide andintroducing the clathrate solution to the contaminated material. Theclathrate may be formed either in situ or ex situ. Similarly, theclathrate may be introduced to the contaminated material in situ or exsitu. It is contemplated that this method may include additional stepssuch as introducing an oxidant and/or activator in addition to the ozoneto the contaminated material and oxidizing the organic compound todestroy at least a portion of the compound.

In another aspect, a method of reducing the concentration of an organiccompound in contaminated material is provided, the method comprisingintroducing an oligosaccharide to the contaminated material, introducingozone to the contaminated material, and forming a clathrate from theozone and the oligosaccharide. The oligosaccharide and the ozone may beintroduced to the contaminated material in any order or simultaneouslyand the introductions may occur in situ or ex situ. It is contemplatedthat this method may include additional steps such as introducing anoxidant and/or activator in addition to the ozone to the contaminatedmaterial and oxidizing the organic compound to destroy at least aportion of the compound.

In another aspect, a method of increasing stability of ozone in water,soil, rock or sediment is provided, the method comprising forming anozone/oligosaccharide clathrate solution, and injecting the clathratesolution into the water, soil, rock or sediment.

In another aspect, a method of reducing the concentration of organiccontaminants in soil, sediment, water or groundwater using chemicaloxidation is provided, the method comprising injecting a cyclicoligosaccharide into a borehole at a remediation site, injecting one ormore oxidants into a borehole at the remediation site, oxidizing atleast a portion of the organic contaminants present at the site, andoxidizing at least a portion of the cyclic oligosaccharide molecules toreduce the cyclic oligosaccharide to fragments that can be utilized bymicrobes as a co-metabolite to promote biodegradation of the organiccontaminant. It is also understood that the organic contaminant canbecome more biodegradable after it is solubilized by the cyclicoligosaccharide and/or partially oxidized by the oxidant(s).

The compounds and methods disclosed herein may be used to remediateorganic compound contamination in situ or ex situ. They may be used inconjunction with known and future methods that employ various oxidantsincluding, for example, ozone, persulfate, permanganate, percarbonateand peroxide. Activators may also be included. In some cases, the ozonecan form a superoxide radical to aid in oxidative processes. Componentsmay be provided (e.g., injected) together or separately. The clathratehost can be recycled and can be recharged with additional ozone.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of this disclosure, and themanner of attaining them, will become more apparent and betterunderstood by reference to the following description of embodimentsdescribed herein taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a graph showing experimental results of ozone concentrationvs. time;

FIG. 2 is a graph showing experimental results of trichloroetheneconcentration versus time;

FIG. 3 is a graph showing experimental results of trichloroetheneconcentration versus time in the presence of cyclodextrin;

FIG. 4 is a graph showing experimental results of pyrene remediation ina soil/groundwater matrix;

FIG. 5 is a graph showing experimental results of change of dissolvedozone concentration over time; and

FIG. 6 is a copy of a photograph depicting the visual results of anindigo colorimetric ozone test.

DETAILED DESCRIPTION

The terms “cyclodextrin” (CD) and “derivitized cyclodextrin” (dCD) areused as they are in the art and include compounds such as alpha, beta,or gamma cyclodextrin and derivatives thereof such as hydroxy-propylbeta cyclodextrin (HP-β-CD), amino-propyl cyclodextrin, carboxy-methylcyclodextrin (CMCD) and randomly methylated beta-cyclodextrin (RAMEB).Cyclodextrin includes derivitized cyclodextrin unless otherwisespecified. Cyclodextrins are cyclic oligosaccharides and, morespecifically, cyclic oligoglucosides.

The term “microencapsulation” is defined as a method of controlledrelease whereby a solid, liquid, or gas is packaged in minute sealedcapsules that release their contents at controlled rates under theinfluence of specific conditions. CDs can be considered as emptycapsules of molecular size that form complexes with guest moleculesresulting in an encapsulation process on the molecular scale.

A “clathrate” or “clathrate compound” is used herein as it is used inthe art and means an inclusion complex having a lattice of at least twomolecules in which one molecule traps the other. The two molecules arenot covalently bonded to each other but are held together by weakerforces such as hydrogen bonds. Clathrates may be referred to ashost-guest complexes or inclusion compounds. An example of a clathrateis a complex of ozone retained within the interior cavity of acyclodextrin molecule. Clathrates are not to be confused withsurfactants and need not function as surfactants. An “ozone clathrate”is a clathrate in which the guest is one or more ozone molecules. A“cyclic oligosaccharide clathrate” is a clathrate in which the host is acyclic oligosaccharide.

Clathrates, such as cyclodextrin clathrates, can microencapsulate ozonein aqueous solution, increasing its solubility and stability.Cyclodextrins are also capable of desorbing organic and inorganiccontaminants from, soils, slurries, sediment and other materials. Thesecompounds also are believed to be biodegradable and do not reactdirectly with oxidants used in chemical remediation. Thus, cyclodextrins(and related compounds) can provide a biodegradable vehicle for bothstabilizing ozone and desorbing organic contaminants.

An ozone clathrate can be formed, for instance, by injecting ozone intowater to produce an aqueous solution (e.g., with a Mazzei injector) andadding a clathrate host component such as an oligosaccharide (e.g.,cyclodextrin). Alternatively, the water may contain the cyclodextrinprior to injection of the ozone into the solution. The solution maycontain ozone/oligosaccharide clathrate as well as unassociated ozoneand unassociated oligosaccharide.

In one aspect, a method of stabilizing ozone to improve the oxidation oforganic contaminants is provided. A clathrate consisting of ozone and acyclic oligosaccharide, such as cyclodextrin, can prolong the in situ orex situ half life of ozone, attenuate the amount of ozone in solutionand provide for an expanded zone of influence at a remediation site. Aclathrate including ozone may also be more soluble in water than ozonealone. Thus the clathrate can provide both enhanced stability andenhanced solubility of ozone. Via a clathrate, ozone can be delivered ina hydrophobic phase that is suspended in a hydrophilic phase. When atarget contaminant is contacted, the contaminant molecule may be drawnto the oxidant by the clathrate or the oxidant may be delivered to thereactive site by the clathrate. The oxidant, which may be ozone, can beassociated with the clathrate, meaning that the ozone ismicroencapsulated by the clathrate and carried in the aqueous solutionand through the zone of contamination as a single ozone clathratecomplex. One or more ozone molecules may be associated with a clathratemolecule and one or more cyclodextrins may be associated with an ozonemolecule. For instance, an ozone molecule may be retained inside acyclodextrin molecule. As a result, the ozone molecule is protected fromambient reducing agents and its activity can be prolonged. This mayprovide a greater zone of influence for a given concentration ofoxidant.

A cyclic oligosaccharide is of a generally toroidal shape that can forma clathrate by retaining one or more ozone molecules in the interiorcavity of the torus. A host-guest relationship between the cyclicoligosaccharide and the ozone is formed in which the ozone is stabilizedvia its stearic attraction to the cyclic oligosaccharide. It is believedthat as a component of the clathrate, the ozone is protected fromreduction by substances that would otherwise contact the ozone moleculein solution. These reducing agents may be numerous in environments suchas ground water and soil. The microencapsulated ozone is isolated fromthese non-target reducing compounds, allowing a greater percentage ofthe ozone to remain for reaction with target contaminants. For in situmethods, this stabilization effect allows a greater percentage of thecompound to be transported in the unsaturated or saturated zone of thesubsurface farther away from the injection point, thus providing for adecreased number of vertical or horizontal injection points. It isbelieved that the cyclodextrin clathrate may also act as a reactor whereguest molecules of both contaminant (e.g., organic solvent) and oxidantmolecules (e.g., ozone) associate with either the hydrophobic cavity orthe hydrophilic hydroxyl groups of the cyclodextrin and come in closecontact with each other. This close stearic interaction can promotereaction between the contaminant and the oxidant molecule.

The use of an ozone clathrate (such as ozone/cyclodextrin) can providefor a stable concentration of ozone in the reaction zone. For instance,initial ozone concentration in solution may be significantly lower whencompared to the concentration typically realized upon introduction of aconventional ozone solution. This means that less ozone may be destroyedby native reducing agents that are not targets of the remediation. Overtime, often a matter of minutes, the ozone concentration may becomehigher when a clathrate is used because the microencapsulated ozone isprotected from reducing agents and is released from the clathrate onlywhen the unassociated ozone concentration drops below a specificconcentration, for example, 1 ppm or 2 ppm by weight. This chemicalequilibrium between the ozone clathrate and free ozone in solution canprovide a consistent concentration of ozone to the reaction zone. Insome embodiments, the solubility of the organic or inorganic hydrophobiccontaminant may be enhanced by the introduction of a clathrate and thecontaminant can be concentrated by the oligosaccharide component of theclathrate. This may also result in more frequent contact between thehydrophobic contaminant and the ozone molecule because the hydrophobiccontaminant may exhibit an affinity for the oligosaccharide that ishosting the ozone.

Examples of cyclic oligosaccharides include cyclic oligoglucosides suchas α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and randomlymethylated β-cyclodextrin (RAIVIEB) A clathrate comprising hydroxypropylβ-cyclodextrin (HP-β-CD) in particular has been shown to provide higherand more stable concentrations of ozone in solution when compared toozone alone. Cyclic oligosaccharides may also be used to form clathrateswith other oxidizing, reducing or radical forming compounds useful inchemical and biological remediation. These compounds may include, forexample, oxygen, hydrogen, peroxide, persulfate, permanganate or otherperoxygen compound. One embodiment includes an ozone/cyclodextrinclathrate, persulfate and hydrogen peroxide. In various embodiments, thepersulfate may be either monopersulfate or dipersulfate.

Compounds capable of forming clathrates may be natural or synthetic.Examples of compounds capable of forming natural clathrates includecyclodextrins, carbon nanotubes, ureas, and zeolites. Natural clathratesmay be biodegradable and may exhibit low, or no toxicity. Manyoligosaccharides are biodegradable in situ. In preferred embodiments theoligosaccharide (e.g., cyclodextrin) is stable for more than a day butdegrades in less than a year (half life) in situ. This can provide forefficient delivery of ozone and desorption of target organic compoundswhile avoiding long term residual injectate contamination, such as canhappen with the use of surfactants.

In one aspect, the present invention relates to the treatment ofmaterial contaminated with undesirable organic or inorganic compoundsthat can be destroyed by oxidation. Material includes, for example,soil, sediment, clay, rock, sand, till and the like (hereinaftercollectively referred to as “soil”). Additional treatable materialsinclude contaminated water and groundwater found in the pore spaces ofsoil and rock, process water resulting from various industrial processesor wastewaters (e.g., tar sand waste water). Material also includes, forexample, “separate-phase” contaminants such as dense and/or lightnon-aqueous phase liquids (NAPL). Material can further include a surfacecontaminated with an undesirable organic or inorganic compound, such asthe inside of a pipe through which liquid or solids flow, or the surfaceof a natural or synthetic fabric. The present invention also relates toa solution for the treatment of suspensions, slurries and solidscontaining chemical warfare agents. Treatment may proceed in situ or exsitu. Contaminants may be treated in the saturated zone, the unsaturatedzone or the smear zone. The use of the clathrate can improve flow ratesthrough the unsaturated zone without sacrificing hydraulic conductivitythat can result from the use of surfactants and other materials designedto release contaminant from the material. A clathrate may also improveresults when used with a sparging system. For example, the clathrate mayenhance the solubility of oxygen, ozone or air in a sparging system,resulting in a greater concentration of reactants in the reaction zone.

ISCO and ESCO technologies can use strong oxidizing agents to treatcontaminated soil by chemically degrading recalcitrant and hazardouschemicals. Such oxidizers include, for example, hydrogen peroxide,Fenton's reagent, ozone, permanganate, percarbonate, activated andunactivated persulfates, and other peroxygens. One key aspect to theability of an oxidizer to function is its ability to permeate throughthe subsurface either above the groundwater table (unsaturated zone) orbelow the groundwater table (saturated zone) while interacting withtarget compounds throughout the entire zone of contamination. Oxidizingspecies, such as ozone and peroxides have relatively short life timeswithin the subsurface ranging from minutes with ozone to hours withperoxides. Persulfates can survive for greater periods, typicallyreported in days. In general, there is a desire to have longer livedactive species available for organic species decomposition in order toincrease the zone of reaction while minimizing the number of injectionpoints throughout the area of subsurface contamination.

ISCO technology can be used alone or in combination with othercomplementary technologies, such as soil vapor extraction (SVE) forremoval of volatile organic compounds from the unsaturated zone,multi-phase extraction for removal of organic contaminants from thesaturated zone, vertical or horizontal recirculation systems in thesaturated zone, or air sparging of the saturated zone. Both ISCO andESCO technologies can be combined with different methods of heatapplication such as radio frequency heating or steam injection fortreatment of soil, water, and sediment. Also, they can be combined withbioremediation for enhanced post oxidation treatment.

Various methods of ISCO delivery have been developed for differentsituations and conditions to improve contact between the contaminant andoxidant. ISCO has been applied to soil and groundwater treatment for thelast decade and the demand for this technology continues to grow andevolve.

ESCO can be applied to soil by several methods including a backhoe,excavator, soil mixing auger, mixing jet, windrow mixer or excavationand placement into a reactor vessel. ESCO can be applied to sediment bydredging and mixing in a reactor vessel. ESCO can also be applied tosolid surfaces such as vehicles and equipment by spraying as describedin U.S. Pat. No. 6,459,011, which is hereby incorporated by referenceherein.

Certain contaminants at concentrations greater than their aqueoussolubility limit exist as non-aqueous phase liquids (NAPLs) in soil,water or sediment. When in water or an aqueous environment, it becomesimportant whether the NAPL has a density lighter than water or greaterthan water. If less dense than water (LNAPLs), the contaminants willfloat and if more dense than water (DNAPLs), they will sink. Examples ofLNAPLs are petroleum hydrocarbons such as gasoline, diesel fuel, andfuel oils. Examples of DNAPLs are various chlorinated organic compoundssuch as tetrachlorethene (PCE), trichloroethene (TCE), polychlorinatedbiphenyls (PCB) or manufactured gas plant (MGP) wastes. Chemicalsassociated with MGP waste include volatile organic compounds (VOCs) likebenzene and toluene, polynuclear aromatic hydrocarbons (PAHs) likepyrene, tar acids like phenol and cresol, creosote, and coal tar pitch.

Ozone can be applied to the unsaturated zone, the saturated zone, and/orthe smear zone. Ozone can be applied to the unsaturated zone using, forexample, vent wells for ozone injection and/or SVE technology whereby avacuum is induced in the subsurface to distribute the ozone through thearea of contamination. Ozone can also be applied to the saturated zoneusing sparging techniques whereby ozone is added with air or pure oxygenand sparged into the groundwater. Ozone is highly reactive and shortlived in the aqueous environment in which soil treatment typicallyoccurs. This limits the radius of influence from either a vertical orhorizontal injection point. Ozone can react with a great number ofcontaminants in a variety of ways including: 1) direct reaction of ozonewith organic compounds, and 2) reaction by free hydroxyl radicals. Thesolubility of ozone in aqueous solution is about 14 mM at 20 degrees C.

There are many factors, such as pH, pressure, temperature, and ionicstrength, which can affect the stability of aqueous ozone. The stabilityof an ozone solution is highly dependent on pH and decreases asalkalinity increases. A higher temperature aqueous solution yieldsfaster ozone depletion. Also, higher ionic strength typicallyaccelerates depletion. Ozone solution stabilization can be considered aseither short-term (less than one minute) or long-term (greater than oneminute). Short-term aqueous ozone stabilization can be practicallyachieved by lowering the pH, decreasing the temperature, involving aninhibitor such as an OH radical scavenger, or lowering the ionicstrength of solution. Buffer agents such as phosphates are not inert toozone. Long term ozone stabilization may be achieved by forming aclathrate with a cyclic oligosaccharide.

Cyclic oligosaccharides may be torus shaped with a hydrophobic interiorand hydrophilic exterior. The interior of the torus may be relativelynonpolar compared to water. In the case of cyclodextrin, the interiorcavity dimension increases with alpha, beta, and gamma cyclodextrin andderivatives thereof. Clathrates of cyclic oligosaccharides are notstatic species. Substrates included in the cavity rapidly exchange withfree substrate molecules in solution. The association of the host andguest molecules and the disassociation of the formed clathrate isgoverned by a thermodynamic equilibrium:

Cyclic Oligosaccharide+Substrate====Cyclic Oligosaccharide*Substrate

Dissociation Constant for 1:1 molar ratio cyclic oligosaccharide toguest substrate is:

K _(D 1:1)=[Cyclic Oligosaccharide*Substrate]/[CyclicOligosaccharide][Substrate]

This is the most common case; however, 2:1, 1:2, 2:2 or even morecomplicated associations may exist simultaneously. With increasingtemperature the solubility of cyclic oligosaccharides typicallyincreases, but the complex stability may decrease.

In many embodiments, the cyclic oligosaccharide is water soluble and maybe, for instance, soluble in an aqueous solution (at neutral pH and atemperature of 25° C.) at a concentration of greater than 10 mM, greaterthan 20 mM, greater than 50 mM, greater than 100 mM or greater than 500mM. Preferred oligosaccharides may have molecular weights in the rangeof, for example, 500 to 5000, 500 to 2000, 500 to 1500, 700 to 1400, 800to 1200 or 900 to 1100. The cyclic oligosaccharides may comprise anappropriate number of saccharide units including, for example, 4, 5, 6,7, 8, 9, 10, 11 and/or 12 saccharide units. The oligosaccharide may benaturally occurring or may be synthetic. Preferred cyclicoligosaccharides may include cyclic oligoglucosides such ascylcodextrins (CD). Cyclodextrins include, for example, α-cyclodextrin,β-cyclodextrin and γ-cyclodextrin as well as derivatives thereof.Derivatives of β-cyclodextrin includes, for example, those derivativesstructured to improve aqueous solubility, such as hydroxypropylβ-cyclodextrin.

In some embodiments, cyclic oligosaccharides may form clathrates withozone at molar ratios in the range of 5:1, 2:1, 1:1, 1:2, 1:3, 1:4, orgreater. A single aqueous solution may include different clathrates thatexhibit different molar ratios of cyclic oligosaccharides and ozone. Insome embodiments the clathrate solution may also contain unassociatedozone and/or unassociated cyclic oligosaccharide. To activate the ozoneto participate in chemical oxidation, the ozone can be released from theclathrate. In one set of embodiments the release can be facilitated by,for example, altering pressure, altering temperature and/or reducing thepH of the solution. For instance the pH of the solution may be reducedby half a pH unit, from 7.0 to 6.5, to provide for the release of ozonefrom the clathrate. This pH reduction may be accomplished in oneembodiment by the in situ decomposition of persulfate. As pH drops, theactivity of ozone increases. This increase in activity results in areduction in the amount of free ozone available and the drop in ozoneconcentration pulls free ozone from the clathrate due to the equilibriumrelationship between the ozone clathrate and free ozone in solution.

Ozone clathrates may be formed in situ or ex situ. Clathrate solutionsmay be injected directly into the saturated zone, unsaturated zoneand/or smear zone or, in other embodiments, the ozone and cyclicoligosaccharide may form a clathrate after entering the saturated zone,unsaturated zone and/or smear zone. For instance, the cyclicoligosaccharide may be introduced into the saturated zone sequentiallywith the ozone. The two components can subsequently associate in situ toform the clathrate. In some embodiments it may be preferred to preparethe clathrate solution prior to injecting the components into theground. This may help reduce the premature and wasteful decomposition ofozone and may reduce side reactions such as oxidation of naturallyoccurring materials in the soil and/or groundwater. Cyclicoligosaccharides have limited reactivity with soil and thus should notinterfere with desired reaction paths. They also do not react with ozoneand do not scavenge hydroxyl radicals, leaving them available fororganic contaminant destruction. Cyclodextrin can be biodegradable insoil. Cyclodextrin does not interact or adsorb to soil as surfactantsdo, which, in the case of surfactants, may contribute to the organiccarbon load in the soil.

The ozone clathrates may be used in conjunction with other oxidationsystems to destroy organic contaminants. Additional useful oxidants mayinclude, for example, any combination of peroxide, persulfate,permanganate, percarbonate and unassociated (non-clathrate) ozone. Theseadditional oxidants may be provided simultaneously with the ozoneclathrate and may be introduced via a common aqueous solution or throughseparate means, such as separate injectors. Additional oxidants may alsobe provided to the contaminated material prior to or after delivery ofthe ozone clathrate. For instance, a groundwater site can first betreated with an ozone clathrate, then with unassociated ozone andfinally with a combination of persulfate and hydrogen peroxide.Unassociated clathrate host (e.g., cyclodextrin) may also be provided tothe contaminated material to facilitate desorption of contaminants.

A remediation system featuring a clathrate may be operated at or closeto ambient temperature which can help reduce the volatilization ofcontaminants. For example, either in situ or ex situ, the clathratesolution can be maintained at a temperature of less than 60° C., lessthan 50° C., less than 40° C. or less than 30° C.

In general, soil treatment for hydrophobic organic contaminants benefitsfrom a two step mechanism involving both desorption from the solid phaseto the aqueous phase followed by flushing and/or either chemical orbiological oxidation. To enhance flushing, surfactants can be circulatedin an aqueous solution so as to desorb hydrophobic organic contaminantsfrom soil into the aqueous phase. Surfactants function by reducing theinterfacial tension at the solid-liquid interphase to desorb organiccontaminants from soil. When surfactants and chemical or biologicaloxidation is used, there are two primary mechanisms that typicallyoccur: 1) adsorbed soil contaminants are first desorbed and thenoxidized in the aqueous phase, or 2) sorbed contaminants are directlyoxidized while sorbed to the soil and also oxidized in the aqueousphase. For strongly sorbed hydrophobic organic contaminants, thedesorption step may be the rate-limiting step in the destruction of thecontaminant.

An ozone clathrate may stabilize ozone and may also provide a vehiclefor desorbing organic contaminants from a solid phase such as soil orsediment. Clathrates are not surfactants or co-solvents but can exhibita similar ability to desorb organic compounds from the soil or sediment.When compared to surfactants or co-solvents, clathrates may exhibitproperties that make them preferable to surfactants. For example, manyclathrates are less likely to form emulsions, can enhance bioremediationby solubilizing the contaminant, can simultaneously desorb organics, aretypically biodegradable and are less likely to mobilize LNAPL or DNAPL,which can make remediation much more difficult. Unlike surfactants,clathrates may have little or no effect on interfacial tension whilestill being useful to remediate NAPL via microencapsulation. As shownbelow in Experiment 2, in at least some cases, clathrates do not add tooxidant demand. In addition, clathrates typically do not result in soilsorption or pore exclusion as surfactants have been found to do.Furthermore, clathrates do not seem to be adversely affected by changesin pH or ionic strength.

In one set of embodiments an ozone clathrate may be used to control therate of oxidation. This rate can be adjusted in response to a change inthe rate of desorption from the material containing the contaminants ofinterest. For instance, if the rate of contaminant desorption is low,the rate of ozone release from the clathrate can be reduced so the ozoneis kept in reserve until oxidizable contaminants become stearicallyavailable. This can be accomplished, for example, by increasing the pHof the solution and can reduce the amount of ozone that would otherwisebe scavenged by various reducing agents that are not the targetcontaminant. If the rate of desorption is high, the rate of release ofozone from the clathrate can be increased, by lower pH for example, tomaximize the rate of reaction with the contaminant. Thus, the system canbe tuned to maximize the rate of destruction while minimizing the amountof ozone required to do so when compared to requirements for treatmentwith unassociated ozone. These rates may also be controlled by, forexample, changing the clathrate host, altering the concentration ofclathrate provided, altering the ozone:oligosaccharide ratio, alteringflow rates of the clathrate solution, altering the ratio ofclathrate:oxidizer, and/or changing the temperature of the system. Insome cases, a combination of different ozone clathrates may be used.

In some embodiments, activators can be added to improve the rate ofreaction of the remediation process. An activator is a chemical orcondition (e.g., temperature) that can be added or altered to improvethe rate of destruction. Activators can include catalysts and changes tothe environment, such as the application of heat. Appropriate activatorsfor oxidation systems may be, for example, heat, an increase in pH, atransition metal such as ferrous, ferric, or zero valent iron, hydrogenperoxide, and/or a hydroxyl radical. Zero valent iron may also be usedalone without an oxidant to dehalogenate certain halogenated compoundssuch as chlorinated organic compounds.

Other reagents may be used in conjunction with the clathrate. Forinstance, complexing agents such as sodium citrate, EDTA, sodium oxalateand tetrasodium pyrophosphate can be added to further enhance desorptionand oxidation of PAH and other compounds. This may be particularlyuseful when heavy metals are present in the matrix. Other compounds suchas surfactants and co-solvents may be used to aid in the desorption ofcontaminants from various matrices. These compounds may be biodegradablesurfactants or biodegradable co-solvents. These include, for example,citrus terpenes such as d-limonene.

The type of oligosaccharide that is chosen may also be useful incontrolling reaction rates. For instance, certain structures andfunctional groups may retain ozone more securely than others. Theability of a specific oligosaccharide to host ozone can be determined byone of skill in the art by repeating experiment 1 (described below) withthe specific oligosaccharide being evaluated.

In another set of embodiments, the density and/or viscosity of clathratesolution may be controlled to improve contact with the contaminant(s).The viscosity of the clathrate solution can be preselected in order toachieve enhanced contaminant contact/reaction efficiencies. Forinstance, higher viscosity solutions may be chosen when high porositysoils are encountered. Likewise, low viscosities may be preferred whensoil porosities are low. Viscosities may be adjusted by, for example,adjusting the clathrate concentration or the ratio of clathrate tounassociated cyclodextrin (or other oligosaccharide). For those targetcontaminants that have a density greater than water (DNAPL), thesolution can be formulated to have a density greater (e.g., >1.0 g/cm³)than water so as to deliver the most clathrate-oxidant directly to thecontaminant. The clathrate solution may have a lower density (e.g., <1.0g/cm³) for those target contaminants that have a density less than water(LNAPL). A lower density may be achieved by, for example, adding anacceptable co-solvent that renders the density of the solution less than1.0 g/cm³. Alternatively, a gas may be introduced to the solution toincrease buoyancy which can improve contact with LNAPL. One method ofcontrolling the density of the clathrate solution is to increase ordecrease the concentration of the clathrate to increase or decrease thedensity of the solution.

In another embodiment, the clathrate may be used to generate asuperoxide radical (anion) such as O₂r. Superoxide radicals may beuseful in oxidizing many organic contaminants. Examples of how asuperoxide radical can be formed are provided below. The concentrationof superoxide radicals can be increased by using the ozone clathrate toprovide a continuously high level of ozone to the solution. OHr=hydroxylradical, HO₂r=perhydroxyl radical, O₂r=superoxide radical.

O₃+H⁺->OHr+O₂ (water reaction)  1)

O₃+OH⁻->HO₂ r+O₂ (water reaction)  2)

O₃+H₂O₂->HO₂ r+OHr+O₂ (hydrogen peroxide reaction)  3)

O₃+OHr->HO₂ r+O₂ (chain reactions from all of the above (1,2,3))  4)

O₃+HO₂ r->O₂ r+OHr+O₂ (chain reactions from all of the above(1,2,3))  5)

In addition,

H₂O₂+OHr->H₂O+O₂ r (reaction between hydrogen peroxide and hydroxylradical)  6)

H₂O₂+SO₄ r->SO₄ ²+HO₂ r+H⁺ (reaction between hydrogen peroxide andsulfate radical)  7)

and;

HO₂ r<->O₂ r+H⁺ (superoxide radical is deprotonated form of perhydroxylradical and is dependent on the pH of the solution)  8)

Ozone clathrates may be useful in the destruction of a number ofcontaminants, both organic and inorganic. These contaminants caninclude, for example, solvents, heavy metals, pesticides, herbicides,fungicides, preservatives, wood preservatives, munitions, explosives,chemical warfare agents, fuels, oils, greases, pharmacologicals,endocrine disruptors (EDC) and viral and/or microbial agents. Classes oforganic compounds that can be treated include both dense and lightnon-aqueous phase liquids (NAPL), dissolved or sorbed organic compounds,volatile organics, semi-volatile organics, chlorinated volatileorganics, non-volatile organics, halogenated organics and heavy metals.Specific compounds that can be remediated include, for example,polychlorinated biphenyls (PCBs); tetrachloroethylene (PCE),trichloroethylene (TCE), trichloroethane (TCA), dichloroethene (DCE),chlorophenols, vinyl chloride; fuel constituents such as benzene,ethylbenzene, toluene, xylene, methyl tert butyl ether (MTBE), tertiarybutyl alcohol (TBA), polynuclear aromatic hydrocarbons (PAHs), dioxins,furans, ethylene dibromide (EDB); DDT, silvex and geosimin. Inorganiccontaminants may include metals, such as lead, arsenic, chromium,mercury, silver, cadmium, nickel and/or cobalt. The use of an ozoneclathrate can reduce target contaminant concentrations by more than 50%,more than 75%, more than 90%, more than 95%, more than 98% or more than99%, by weight. In different embodiments, absolute levels ofcontaminants can be reduced to less than 1%, less than 1,000 ppm, lessthan 100 ppm, less than 10 ppm, less than 1 ppm, less than 100 ppb orless than 10 ppb, by weight.

The method described in US Patent Publication No. US2008/0008535A1 toBall, and which is hereby incorporated by reference herein, can be usedto apply a clathrate solution to a remediation site. The technologydescribed herein may also be useful when applied to other remediationmethods. Examples of other methods include gravity feed, caissons,trenches, injection and/or extraction wells, recirculation wells(vertical or horizontal), push-pull injection/extraction or reactivewalls. Examples of in situ sediment remediation methods include harrows,in situ ozonators and reactive caps. Examples of ex situ methods forsoil, water, or sediment include many types of batch, semi-batch, plugflow, slurry-phase reactors, or pressure-assisted reactors.

The ozone clathrate may be provided over a broad range ofconcentrations. Many clathrate forming compounds, such as cyclicoligosaccharides, are highly soluble in aqueous solutions. For instance,cyclodextrin can be provided at concentrations of greater than 0.1 mg/L,greater than 1 mg/L, greater than 10 mg/L, greater than 100 mg/L,greater than 1000 mg/L, greater than 5 g/L, greater than 10 g/L, greaterthan 100 g/L, or greater than 200 g/L. Clathrate concentrations may besimilar. A saturated ozone solution used in the field is typically at aconcentration of about 10 mg/L. By microencapsulating ozone in aclathrate, the ozone concentration can be significantly increased, togreater than 20 mg/L, greater than 50 mg/L, or greater than 100 mg/L, orgreater than 500 mg/L. In addition, the oligosaccharide portion of theclathrate can be re-charged with ozone after the ozone has been releasedfrom the clathrate into solution. This re-charging may take place aboveground or in situ.

A clathrate solution may be used ex situ or in situ and may be providedat a rate appropriate for controlled destruction of the targetcontaminants. Injection rates may also be controlled in response todepth, soil conditions, permeability, number of injectors and previoustreatment. In some embodiments, the clathrate solution can be provided(e.g., injected) at a rate of 1 L/min, 5 L/min, 10 L/min, 50 L/min, 100L/min or more.

The following provides an example of how a clathrate solution may beused with the system provided in U.S. Patent Publication No.US2008/0008535A1. Initially, a super-saturated ozone in water solutionis mixed with a cyclic oligosaccharide using, for instance, an in-linestatic mixer, a venturi, a porous metal sieve/diffuser or a pressurevessel or combinations thereof and injected into the subsurface at aspecified flow rate and for a specified time selected based on theconditions at the site. Hydrogen peroxide (which may be buffered) andbuffered persulfate may be either simultaneously or sequentiallyinjected into the subsurface. The same or different injection wells maybe used for the different components. The chemical oxidation process maybe monitored by taking measurements of, for example, pH, ORP,conductivity, temperature, dissolved oxygen, dissolved ozone, hydrogenperoxide, persulfate, sulfate and phosphate. If monitoring indicatesthat contaminants remain after several weeks, the procedure may berepeated using the same or different injection wells.

In another embodiment a solution of ozone and a solution of a cyclicoligosaccharide may be introduced independently to the saturated zone,unsaturated zone or smear zone. For instance, a cyclodextrin solutionmay be injected into the ground simultaneously or sequentially (beforeor after) with a solution or supersaturated solution of ozone. Uponmixing, the clathrate may be formed in situ.

In another embodiment, a clathrate solution may be produced by addingsolid cyclic oligosaccharide to an ozone solution. For instance,powdered hydroxypropyl beta cyclodextrin may be added to asupersaturated ozone solution at atmospheric pressure. In this manner,foaming that might occur by bubbling ozone through a cyclicoligosaccharide solution can be avoided while still achieving highclathrate concentrations.

In another set of embodiments a cyclic oligosaccharide can be used toremediate soil, sediment, surfaces, and water samples with or withoutozone. Cyclodextrin is exemplary of these cyclic oligosaccharides andmay be preferred, although other cyclic oligosaccharides can be equallyuseful.

It has been found that cyclic oligosaccharides such as cyclodextrin canperform a variety of functions in a remediation project. Cyclicoligosaccharides can act as a carrier for oxidants and/or activators.They can solubilize a wide range of organic contaminants such as flameretardants including polybrominated diphenyl ethers (PBDE),perfluoroalkyl compounds; hydrocarbon based fuels (gasoline, diesel, #2,#4 and #6 fuel oils, jet fuel, kerosene), halogenated organics, MTBE,ethylene dibromide, pesticides, herbicides, PCBs, dioxins, furans,endocrine disruptors, and polycyclic hydrocarbons as well as non-aqueousphase liquids (NAPLs) either dense (DNAPL) or light (LNAPL). Cyclicoligosaccharides can also serve as an energy source for bioremediationand can promote biological activity as a co-metabolite that can furtherremediate contaminated soil or water. Thus, in a single process, cyclicoligosaccharide can deliver an oxidant or activator, solubilize anorganic contaminant and promote biological remediation. These differentfunctions can be controlled by regulating the ratios of cyclicoligosaccharide, oxidant and contaminants. Contaminant concentration ata site can be estimated using methods known to those of skill in theart. Oxidant concentrations can be determined by knowing the efficiencyof the oxidation system for a target contaminant. The amount of cyclicoligosaccharide can be determined once the practitioner decides whatoxidants and/or activators are to be delivered to a site and the amountof residual cyclic oligosaccharide that is desired. Ratios of cyclicoligosaccharide to oxidant to contaminant (on a molar basis) maypreferably range from 1000:1000:1 to 1:1:1 to 1:1000:1000. In somecases, the amount of oxidant can be increased to achieve greater levelsof destruction. For instance, the amount of oxidant to contaminant maybe 2:1, 5:1 or 10:1. Oxidant type and concentrations may also be chosento provide an environment that promotes microbial activity. Materialssuch as phosphates may also be included and can provide a nutrientsource for microbes as well as a pH buffer. pH may be controlled between5 and 10 or 6 and 9 to promote microbial activity. Other nutrients suchas nitrogen and trace minerals can be added to promote biodegradation.Examples of a nitrogen source include ammonium persulfate and nitrousoxide gas.

Specific cyclic oligosaccharides can be chosen to form a clathrate witha specific guest molecule. For example, a chosen cyclic oligosaccharidemay include a large cavity for forming a clathrate with a largeactivator, oxidant or contaminant. Preferred oligosaccharides can befound and selected using the following technique. First, a solution ofcandidate cyclic oligosaccharide compound(s) is formed and astoichiometric amount of the target activator, oxidant or contaminantcompound is added. The solution is mixed well and the pH is controlledto promote clathrate formation. Effective formation of a clathrate canbe determined using spectrometric techniques or by nuclear magneticresonance (NMR) to determine how much free compound is unassociated withthe oligosaccharide.

An oligosaccharide such as cyclodextrin can be delivered to the site ofcontamination by injecting an aqueous solution of the compound through abore hole into the saturated, unsaturated or smear zone. It may be mixedwith an oxidant stream such as ozone, persulfate or peroxide,percarbonate, permanganate, perphosphates or may be deliveredindependently. The oligosaccharide may be delivered before or afteradministration of the oxidant(s). A gas may be used to aid in dispersingthe oligosaccharide and can help to mix the oligosaccharide with thegroundwater media. The gas may be introduced with, or separately from,the oligosaccharide. Appropriate gases include air, oxygen, ozone,nitrogen, and nitrous oxide. The oligosaccharide may be delivered at avariety of pHs, including 3.0 to 11.0, 5.0 to 9.0 and 6.0 to 8.0. Thesolution may be buffered, for example, by a phosphate solution such assodium phosphate. Phosphate can also aid in precipitating metals in situand may be added in quantities greater than that necessary for proper pHcontrol. Phosphates can also be used to promote microbial activity forbiodegradation.

Cyclic oligosaccharides may be used in conjunction with one or morechemical oxidants that can be used in soil, sediment, surfaces, waterand groundwater remediation. For instance, cyclic oligosaccharides maybe used with peroxide, persulfate, permanganate, percarbonate, ozone,perphosphates or any combination thereof. In different cases, cyclicoligosaccharides may or may not form a clathrate with the oxidant. Forexample, ozone may form a clathrate while permanganate does not. Cyclicoligosaccharides may also be used in combination with activators such asorganic or inorganic activators. Activators are materials that are notoxidizers themselves but instead promote the oxidation of organiccontaminants with other oxidizers such as peroxide, persulfate,permanganate, percarbonate and ozone. Inorganic activators include iron(ferrous, ferricor, and zero valent) and in general, divalent ortrivalent transition metals. Ozone can also act as an activator. Aclathrate can also be formed using native iron that is present in situ.Activators may be released from the clathrate by, for example, adjustingthe pH of the solution. For instance, iron can be released from a cyclicoligosaccharide clathrate by lowering the pH of the solution below pH5.0 or raising the pH above pH 9.0.

A cyclic oligosaccharide can be used to deliver an oxidant or activatorin an aqueous carrier either in situ or ex situ. An activator or oxidantcan be added to an aqueous solution of a cyclic oligosaccharide and theactivator or oxidant may form a clathrate with the oxidant or activator.This may, for example, improve solubility and stability of the oxidantor activator. For instance, an inorganic activator such as iron can forma clathrate with a cyclic oligosaccharide and can then be delivered tothe saturated, unsaturated or smear zones. The clathrate may thenrelease the activator or oxidant resulting in free activator or oxidantand either free cyclic oligosaccharide or a decomposition productthereof. The cyclic oligosaccharide may allow the activator or oxidantto be carried further into the hydrophobic region of the site than wouldbe possible in the absence of the cyclic oligosaccharide.

Cyclic oligosaccharides such as cyclodextrin can solubilize organiccontaminants that may be present on a surface or in the water, soil,sediment or groundwater. The organic contaminants may be adsorbed on, orretained by, sand, rock, clay and/or organic material that is present atthe contaminated site. Cyclic oligosaccharides typically act unlikesurfactants in that the cyclic oligosaccharides do not form micelles anddo not have a polar head and hydrophobic tail. Cyclic oligosaccharidessuch as cyclodextrin have a hydrophobic inner cavity and a hydrophilicexterior wall. Therefore, while it has been found that cyclicoligosaccharides can help solubilize organic contaminants in situ and exsitu, this is typically done in the absence of micelle formation.Nonetheless, cyclic oligosaccharides have been found to be effective atassociating with organic contaminants and releasing them from soil,sediment, DNAPL and LNAPL phases into the aqueous phase where they canbe destroyed by oxidants in aqueous solution. Cyclic oligosaccharidescan act as carriers for oxidants and activators while surfactants aretypically not capable of this and are limited to aiding in thesolubilization of contaminants.

Surfactants may be biodegradable or may be stable over the long term.They may also be destroyed by the oxidants being used or may be stablein the presence of these oxidants. In one set of embodiments, a cyclicoligosaccharide can be used in conjunction with an anionic surfactantbased on sulfate, sulfonate, or carboxylate anions. These includesurfactants such as sodium dodecyl sulfate (SDS); or nonionic surfactantbased on alkyl polyethylene oxide and its copolymers, alkylpolyglucosides, fatty alcohols, cocamide MEA, and such as thepolysorbates, Tween 20 or Tween 80; or anionic/nonionic mixtures such asSimple Green® manufactured by Sunshine Makers, Inc. Other surfactantsthat can be used include: Alfoterra®, brand of branched alcoholpropoxylate sulfate, sodium salt anionic surfactants manufactured bySasol North America; Citrus Burst #1, #2, and #3 and EZMulse® brand ofcitrus based surfactants manufactured by Florida Chemical Company. Thecyclic oligosaccharide and the surfactant may act in a complementarymanner by solubilizing different compounds or by solubilizing the samecompound at different rates. When compared to surfactants, the cyclicoligosaccharide may also be more effective at desorbing organiccontaminants from specific materials. Vegetable oils, fatty acids, fattyacid methyl esters, from sources such as soy oil, sunflower oil, orcanola oil can also be used as a co-solvent in conjunction with cyclicoligosaccharides and surfactants to aid in desorption. Citrus derivedoils such as d-limonene can also be used as a co-solvent. Chelatingagents such as citric acid, acetic acid, EDTA, phosphonates can be addedto assist in transporting activators or to bind natural metals. Theaddition of heat or hot water can also be used to improve the desorptionand biodegradation aspects of the process.

Remediation of contaminated materials through the use of chemicaloxidation can be followed by bioremediation. Bioremediation may commencespontaneously after chemical oxidation procedures but often may need tobe primed by inoculating with bacteria and/or nutrients. Cyclodextrinand other cyclic oligosaccharides can serve as a energy source forco-metabolism by bacteria but the compounds are typically stable andrequire significant time in situ before bacteria are able to digest andutilize the polysaccharides. However, by partially oxidizing theoligosaccharide with a chemical oxidant such as persulfate or peroxide,for example, the structure of the oligosaccharide is partiallydecomposed and the resulting fragments of the oligosaccharide canprovide an immediate energy source to any bacteria that may be present.These fragments may include, for example, mono, di and trisaccharides.The site may also be inoculated with bacteria to accelerate biologicalactivity. The presence of cyclic oligosaccharide fragments can providean immediate boost to the biological activity that results in faster andmore complete bioremediation that can occur subsequent to or duringchemical oxidation processes. The biological activity may have longlasting residual effects that provide for remediation down to very lowcontaminant levels after completion of chemical oxidation. Furthermore,the bioremediation can help to destroy additional organic contaminantsthat may migrate to the site after completion of the chemicalremediation process.

In one example, a remediation process may proceed as described below. Asite may be contaminated with a variety of poly aromatic hydrocarbons(PAH) present in the saturated and unsaturated zones. The site mayinclude a DNAPL layer. Several wells are drilled at the site providingaccess to the saturated zone. Aqueous solutions of oxidants such asperoxide, persulfate and ozone may be injected into the saturated zone.Concurrently, a solution of a cyclodextrin/iron clathrate is providedeither together with one of the oxidants or as a separate stream. Amixing gas may also be injected such as through a sparger. After beinginjected into the saturated zone, the iron leaves the clathrate andserves as an activator to promote the oxidation of organic materialspresent in the saturated zone. The cyclodextrin, now free of the iron,migrates through portions of the saturated or smear zones andsolubilizes hydrocarbons that are adsorbed on the surrounding soil,sediment, and rock. The solubilized hydrocarbons are now associated withthe cyclodextrin, drawn into the aqueous phase, and are subjected tooxidation from the oxidant or combination of oxidants that may bepresent. During the oxidation process, the organic contaminant ismineralized and the cyclodextrin is fragmented. These fragments can thenmetabolized by native or inoculated bacteria which use the cyclodextrinfragments as an energy source to increase the size and activity of thebacterial colony. These bacteria may then proceed with metabolizing anyremaining organic contaminants or portions of organic contaminants thatare present. The bacteria may remain in situ for months or years and canreduce the concentration of organic contaminants that enter the area bytransport from adjacent areas or via desorption from existing materials.

In a single operation involving desorption, chemical oxidation, andbio-oxidation, any dissolved organic contaminant, organiccontaminant/cyclodextrin complex and dissolved cyclodextrin may besimultaneously destroyed using one or more oxidants. For example, theconcentration of the contaminant, the contaminant/cyclodextrin complexand the free cyclodextrin may each be reduced by more than 50%, morethan 75% or more than 90% by weight.

In another embodiment a cyclic oligosaccharide may be selected to form aclathrate having properties that cause it to reside in a particularportion of the soil or water column. For instance, if the targetcontaminant is a dense compound the combination of the cyclicoligosaccharide and activator or oxidant are chosen to produce aclathrate denser than water so that the clathrate will concentrate inthe vicinity of the contaminant. This can allow for maximization ofcontact of the contaminant with the oxidant or activator while reducingthe use of oxidant that never comes into contact with the targetcontaminant. The cyclic oligosaccharide can form a clathrate with anactivator and both the resulting clathrate and oxidant can be chosen tobe of greater, lesser or equal density to water. For instance, if theclathrate density is greater than 1.0 it will tend to sink within thesoil and groundwater media. When treating DNAPL, for instance, thisdenser clathrate will serve to concentrate active components, such asoligosaccharide, oxidant and/or activator in the lower portion of thesaturated zone close to, or in contact with, the DNAPL. Very little, ifany, of these compounds will be wasted in areas above the DNAPL thatcontain little or no contamination.

Experiment 1A

An experiment was conducted to determine how the stability of an aqueousozone solution compares to the stability of an aqueous solution of aclathrate comprising ozone and hydroxypropyl-β-cyclodextrin. A firstbubble column contained DI water. A second column contained a 20 mM(26.2 g/L) solution of hydroxypropyl-β-cyclodextrin in DI water. Eachcolumn was ozonated for approximately 10 minutes. After ozonation, eachcolumn was analyzed for ozone (Analytical Technologies Inc. Model#Q45H/64) and ORP (Orion Model #920A ion specific electrode). Readingswere taken each minute for the first 15 minutes and every 5 minutesthereafter until ozone concentrations were seen to level off tobackground levels. Results are provided below in Table 1 (NA=NotAnalyzed) and indicate the maintenance of a much higher free ozoneconcentration in the clathrate solution (about 2 ppm) than in the pureozone solution (<1 ppm). For example, as seen in FIG. 1, even after twohours the ozone concentration in the clathrate solution (pH 6.8) wasstable at about 2 ppm while the ozone concentration in the pure ozonesolution dropped below 2 ppm in about 20 minutes and below about 1 ppmin an hour. The clathrate provided for a more consistent level of ozonethroughout the two hour time window while the sample without theclathrate exhibited very high initial concentrations that tailed offmore quickly when compared to the clathrate sample.

TABLE 1 O₃ Concentration (mg/L) Time (min) O₃ O₃ + CD 0 9 9 1 8.6 3 2 73.5 3 6.4 2.6 4 6 2.5 5 5 3.5 6 4.4 1.8 7 3.5 1.9 8 3.2 2.8 9 3 2.3 102.7 2.6 11 2.5 2.8 12 2.3 2.9 13 2.2 4.7 14 2.1 2.7 15 2 2.4 20 1.7 2.625 1.5 2.5 30 1.4 4.7 35 1.3 1.9 40 1.2 2.3 45 1 2.7 50 1 2.3 55 1 2 601 2.2 65 1 2.3 70 1 2.5 75 NA 2 80 NA 1.9 85 NA 2.3 90 NA 2.1 95 NA 2.1100 NA 2.6 105 NA 2.5 110 NA 2.2 115 NA 2.4 120 NA 2.1 960 NA 2.1

Experiment 1B

Experiment 1B was performed to provide confirmation of the experiment 1Aresults using a different analytical method for ozone analysis based ontitration. The experiment, methods, and findings are discussed here.

The experiment illustrates that the presence of cyclodextrin can affectand stabilize the dissolved ozone concentration in an aqueous system. Inone test, the apparent half life (by probe) of ozone in a 0.5%cyclodextrin solution was reduced from around 13 minutes to about 1minute. This means the formed ozone clathrate sequesters the ozone andrenders it undetectable by the probe. To determine the dissolved ozoneconcentrations below the detection limit of the probe (0.1 mg/l), theIndigo Colorimetric Method (Standard Methods) was used. In this method,free ozone destroys the blue indigo color. The grade of decoloration canbe measured spectrophotometrically to quantify the ozone concentration.The change in color is instantaneous.

In another test, indigo solution was combined with acyclodextrin-stabilized ozone solution, the solution did not decolorizeinstantaneously. It took 80 minutes for the solution to decolorizecompletely. This indicates that over the course of 80 minutes theequivalent of 0.5 mg/l (the upper detection limit for this method)dissolved ozone was released from the cyclodextrin/ozone clathrate tothe aqueous phase to react with the indigo. FIG. 6 displays thisphenomenon in a time-series of pictures taken over 80 min. The initialpicture was taken when the dissolved ozone probe read 0.0 mg/l (ND). Thesamples in each picture are, from left to right, a deionized watercontrol, a CD control, t=0 min, t=5 min, t=15 min, t=30, t=45 min, t=80min, t=100 min, t=130 min and t=220 min. The results show that even thesample drawn 80 minutes after no dissolved ozone could be detected bythe probe contained at least 0.5 mg/l of cyclodextrin-complexed ozonewhen tested using the Indigo Colorimetric Method. FIG. 5 shows theseresults analytically, i.e. based on the continuously metered ORP values.The fact that the ORP was still greater than 1,000 mV after 15 min whenthe ozone probe failed to detect any free ozone and greater than 600 mVafter 100 minutes shows the continued activity of ozone in solution.

These results mean that cyclodextrin may be used to prolong the activityof aqueous ozone, thereby increasing the oxidant's reaction time andeffectiveness. This is especially beneficial for in-situ applicationswhen the goal is to deliver ozone deep into the contaminated soilformation.

Experiment 1B verified the results of experiment 1A that the cyclicoligosaccharide (HP-β-CD) does form a clathrate and that the clathrateslowly releases ozone into solution as determined visually andspectrophotometrically.

Experiment 2

A second experiment was conducted to determine what negative interactionmay exist, if any, between oxidants and hydroxypropyl-β-cyclodextrin inthe presence of trichloroethylene (TCE) at a concentration exceeding thesolubility limit of TCE in water. Eight samples were developed toanalyze remedial efficiencies of the persulfate/ozone/hydrogen peroxidesystem described in U.S. Patent Application Publication No.2008/0008535A1. The experiment was run with and without the presence ofHP-β-CD. The reactor composition was as follows:

1) TCE & Phosphate Buffer

2) TCE, HP-β-CD & Phosphate Buffer

3) TCE, Ozone & Phosphate Buffer

4) TCE, Ozone, HP-β-CD & Phosphate Buffer

5) TCE, OxyZone & Phosphate Buffer

6) TCE, OxyZone, HP-β-CD & Phosphate Buffer

7) TCE, Oxygen & Phosphate Buffer

8) TCE, Oxygen, HP-β-CD & Phosphate Buffer

Reactors were 1000 ml HDPE bottles, and were secured on a LABLINEMulti-Magnestir magnetic stirrer and were stirred for 26 hours at 20° C.Samples were taken from the reactors using a peristaltic pump and werestored in 43 ml VOAs. Samples were taken at 0, 1.75, 6, and 26 hours.The concentrations of the compounds in the reactors were as follows:

Na₂S₂O₈=65 g/LH₂O₂=125 mg/L

HP-β-CD=5 g/L

TCE=2000 mg/L

Buffer=3.44 g/L Monobasic Potassium Phosphate

-   -   4.54 g/L Dibasic Potassium Phosphate

Reactors treated with gas received 50 mL/min of either pure oxygen gasor 6% ozone gas by weight. This is equivalent to approximately 3.2mg/min of ozone in the reactors treated with ozone (Reactors 3-6).

Results are provided below in Table 2 (and graphically in FIGS. 2 and 3)and indicate that persulfate/ozone/hydrogen peroxide and HP-β-CD do notinteract in a negative manner. The presence of HP-β-CD decreased theoxidation rate, as the TCE concentration for persulfate/ozone/hydrogenperoxide alone at 6 hours was 283 ppb, while forpersulfate/ozone/hydrogen peroxide with HP-β-CD the TCE concentration at6 hours was 96.9 ppm. However, the TCE concentration at 26 hours withoutHP-β-CD with HP-β-CD were 73.5 ppb and 75.5 ppb, respectively. IfHP-β-CD was generating oxidant demand, the HP-β-CD sample would notreach the same TCE destruction levels as the sample without the HP-β-CD.

The results also demonstrate a significant reduction in the oxidationrate and efficiency of ozone alone when HP-β-CD is in solution,potentially by the HP-β-CD inhibiting contact between ozone and TCEtrapped within the HP-β-CD cavity. Additionally, the results show thatthe presence of HP-β-CD inhibits TCE volatilization. This isdemonstrated by the retention of TCE in the control sample containingHP-β-CD (sample 2) relative to the control sample without HP-β-CD(sample 1). This second point is further evidence for uptake of TCE intothe HP-β-CD cavity. Therefore, the cyclic oligosaccharide (HP-β-CD)stabilized the ozone in solution, decreased the contaminant losses dueto volatilization and did not adversely affect the oxidation capacity ofthe system which included ozone, persulfate and hydrogen peroxide.

TABLE 2 TCE Concentration (mg/L) Time (hrs) Sample 1.75 6 26 TCE 1030644 256 TCE + CD 984 837 685 TCE + O₃ 444 96 0.162 TCE + O₃ + CD 1065.86 5.83 TCE + S₂O₈ + H₂O₂ + O₃ 220 0.283 0.0735 TCE + S₂O₈ + H₂O₂ +O₃ + CD 316 96.9 0.0755 TCE + O₂ 555 386 137 TCE + O₂ + CD 321 226 168

Experiment 3

Another experiment was conducted to evaluate the effect of an ozoneclathrate on the potential for enhanced desorption and degradation ofstrongly sorbed organic contaminants such as polycycylic aromatichydrocarbons (PAHs). Pyrene was used as the target compound to berepresentative of PAHs sorbed onto soil in a soil and groundwatermatrix. Pyrene was solubilized in methanol and the solution was mixedwith the sand thoroughly. The methanol was subsequently evaporated undera fume hood leaving the pyrene adsorbed onto the sand. The sand/pyrenematerial was allowed to sit for three days prior to analysis for pyreneconcentration and its use in the experiments. Eight samples weredeveloped to analyze remedial efficiencies of sodium persulfate,hydrogen peroxide, and ozone with and without the presence of HP-β-CD.The reactor composition was as follows:

9) Pyrene Sand & Deionized Water

10) Pyrene Sand, Oxygen & Deionized Water

11) Pyrene Sand, Ozone & Deionized Water

12) Pyrene Sand, HP-β-CD & Deionized Water

13) Pyrene Sand, Oxygen, HP-β-CD & Deionized Water

14) Pyrene Sand, Ozone HP-β-CD & Deionized Water

Semi-batch reactors were 1200 ml borosilicate glass columns for 24 hoursat 20° C. fitted with inlet and outlet for ozone or oxygen gas andoff-gas. One pore volume (600 mL) of deionized water was added to eachcolumn. After the reaction period, sand samples were taken from thecenter of the columns and stored in 8 oz amber glass jars. The initialconcentrations of the compounds in the reactors were as follows:

HP-β-CD=5 g/L

Pyrene=500 mg/kg

Reactors treated with gas received 50 mL/min of either pure oxygen gasor 6% ozone gas in oxygen gas by weight. This is equivalent toapproximately 3.2 mg/min of ozone in the reactors treated with ozone(Reactors 2-3, 5-6).

Sand samples were analyzed by GC/MS using EPA Method 8270 for PAHs.Results are provided below in Table 3 (and in FIG. 4) and indicate thatthe Ozone/HP-β-CD clathrate provides the greatest reduction in pyreneconcentration in soil, from an initial concentration of approximately500 ppm to 101 ppm. The presence of HP-β-CD alone decreased theconcentration of pyrene in sand to 238 ppm, indicating a significantdesorption effect relative to deionized water alone, which resulted in apyrene concentration of 490 ppm.

TABLE 3 Pyrene Concentration Sample (mg/kg) Pyrene 490 Pyrene + CD 238Pyrene + O₂ 335 Pyrene + O₂ + CD 231 Pyrene + O₃ 180 Pyrene + O₃ + CD101

It is to be understood that this disclosure is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thedrawings. The embodiments herein are capable of other embodiments and ofbeing practiced or of being carried out in various ways. Also, it is tobe understood that the phraseology and terminology used herein is forthe purpose of description and should not be regarded as limiting. Theuse of “including,” “comprising,” or “having” and variations thereofherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. Unless limited otherwise, the terms“connected,” “coupled,” and “mounted,” and variations thereof herein areused broadly and encompass direct and indirect connections, couplings,and mountings. In addition, the terms “connected” and “coupled” andvariations thereof are not restricted to physical or mechanicalconnections or couplings.

The foregoing description of several methods and embodiments has beenpresented for purposes of illustration. It is not intended to beexhaustive or to limit the claims to the precise steps and/or formsdisclosed, and obviously many modifications and variations are possiblein light of the above teaching. It is intended that the scope of theinvention be defined by the claims appended hereto.

What is claimed is:
 1. A method of reducing the concentration of anorganic compound in a contaminated material, the method comprising:forming a clathrate comprising ozone and a cyclic oligosaccharide; andintroducing the clathrate to the contaminated material.
 2. The method ofclaim 1 further comprising the step of introducing at least one oxidantin addition to the ozone to the contaminated material.
 3. The method ofclaim 2 wherein the at least one oxidant comprises at least one of apersulfate compound, a permanganate compound, a percarbonate compoundand a peroxide compound.
 4. The method of claim 2 further comprisingintroducing an activator to the contaminated material.
 5. The method ofclaim 1 further comprising the step of oxidizing at least a portion ofat least one organic contaminant present in the contaminated material.6. The method of claim 1 further comprising altering a rate at which theozone is released from the clathrate by altering the pH of a fluidcomprising the clathrate.
 7. The method of claim 1 further comprisingdesorbing or solubilizing an organic compound from the contaminatedmaterial with the clathrate.
 8. The method of claim 1 wherein the cyclicoligosaccharide is cyclodextrin.
 9. A method of reducing theconcentration of an organic compound in a contaminated material, themethod comprising: forming a clathrate solution comprising ozone and acyclic oligosaccharide; introducing the clathrate solution to thecontaminated material; and introducing at least one oxidant in additionto the clathrate to the contaminated material.
 10. The method of claim 9wherein the at least one oxidant comprises at least one of a persulfatecompound, a permanganate compound, a percarbonate compound and aperoxide compound.
 11. The method of claim 9 further comprisingintroducing an activator to the contaminated material.
 12. The method ofclaim 9 further comprising the step of oxidizing at least a portion ofat least one organic contaminant present in the contaminated material.13. The method of claim 9 further comprising altering a rate at whichthe ozone is released from the clathrate by altering the pH of a fluidcomprising the clathrate.
 14. The method of claim 9 wherein theclathrate is introduced to the contaminated material through aninjection well.
 15. The method of claim 9 further comprising desorbingor solubilizing an organic compound from the contaminated material withthe clathrate.
 16. The method of claim 9 wherein the cyclicoligosaccharide is cyclodextrin.